The Effect of Phenylephrine and Ephedrine on Microvascular Blood Flow

• Status: Unknown status
• Trial end date: 2015-08-01
• Target enrollment: 0
• Participant gender: Male

Summary

During operations to treat abdominal problems the blood pressure can fall, resulting in falls in blood flow to the vital organs. This fall can be treated by the administration of drugs that cause constriction of blood vessels. Although these drugs correct falls in blood pressure, it is unclear what effect they have on blood flow from the heart and to the vital organs.

In this study of healthy volunteers we aim to better understand the changes in blood flow in both small and large vessels that occur in response to administration of these drugs. To do this we will use two different techniques of ultrasound imaging. A narrow (4-5mm) ultrasound probe will be inserted into the oesophagus via a nostril to measure blood flow in a major blood vessel. A second probe will rest on the abdomen and will record changes in blood flow in small vessels of the liver. Two drugs which raise the blood pressure via different mechanisms will be administered and the changes in flow from the heart and to vital organs will be measured and compared.

• Accepts Healthy Volunteers?: Accepts Healthy Volunteers

Details

• Lead Sponsor: University of Nottingham
• Treatments: Ephedrine; Oxymetazoline; Phenylephrine; Pseudoephedrine

Criteria

Inclusion Criteria:

• Aged 18-60 years

• Male

• Able to consent in English by themselves

• Absence of any exclusion criteria

Exclusion Criteria:

• A BMI < 20 or > 28 kg•m2

• Active cardiovascular disease: uncontrolled hypertension (BP > 140/90), angina, heart failure (class III/IV), arthymia, right to left cardiac shunt or recent cardiac event

• Individuals taking alpha or beta-adrenergic blocking agents, monoamine oxidase inhibitors, tricyclic antidepressants, serotonin or noradrenaline selective reuptake inhibitors, quinidine, cardiac glycosides or buspirone (or who have ceased taking them in the previous 14 days¬)

• Cerebrovascular disease: previous stroke, aneurysm (large vessel or intracranial)

• Peripheral vascular disease

• Metabolic disease: hyper and hypo parathyroidism, untreated hyper and hypothyroidism, Cushing's disease, types 1 or 2 diabetes

• Active inflammatory bowel disease, or renal disease

• Known prostatic hypertrophy

• Malignancy

• Clotting dysfunction

• Previous oesophageal surgery

• Individuals with a known history of oesophageal varices

• Individuals with a known history of epistaxis

• Family history of early (<55y) death from cardiovascular disease

• Known sensitivity to SonoVue, ephedrine or phenylephrine

• Participants who have taken part in any other research study in the last three months which involved: taking a drug; being paid a disturbance allowance; having an invasive procedure (eg blood sample >50ml, muscle biopsies) or exposure to ionising radiation.